Stabilized dry rosin size



Patented Oct. 20, 1942 STABILIZED DRY ROSIN SIZE Arthur C. Dreshfleld, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing.

Application December 4, 1940,

Serial No. 368,457 7 8 Claims. 1 (11106-218) This invention relates to an improvement in rosin size and in particular concerns dry saponifled rosin size compositions stabilized against atmospheric oxidation.

As is well known, rosin size may be prepared and utilized either in dry form or as a liquid or paste in admixture with water. The dry form, however, is in general deemed the most satisfactory because of its ease and economy of shipment, the type of dry rosin size prepared by spray-drying saponified or partially saponified rosin being especially desirable because of its low density and h gh rate of solution in water.

The dry forms of rosin size, particularly the type formed by spray-drying, however, are disadvantageous in that they have a strong tendency to oxidize and spontaneously decompose in the presence of air. Where, as is not uncommon, some free rosin is contained in the size, there is even a greater tendency to oxidize. Such oxidation, and consequent heating, is not only highlydeletcrious to the size itself but. presents a considerable fire hazard during storage and shipment.

I have now found that dry rosin sizes comprising saponified rosin or saponified abietic acid may be effectively stabilized against oxidation by the addition of a small proportion of certain ketone-amine condensation products which act as anti-oxidants. Dry rosin size stabilized in this manner may be stored for long periods or time without danger of decomposition by oxidation or spontaneous combustion.

The ketone-amine condensation products which may be employed in preparing stabilized dry rosin size compositions according to the invention are those prepared by condensing an aliphatic ketone, e. g., acetone, diethyl ketone,

methyl ethyl ketone, diisopropyl ketone, etc.,

with a secondary aromatic amine of the benzene or naphthalene series, e. g., diphenylamine, phenyl beta naphthylamine, p,p'-dinaphthylp-phenylenediamine, dinaphthylamine, etc., in

the presence of a suitable catalyst, with or With-i obtained.

While any of such condensation products may be employed as anti-oxidants ,for dry rosin size,

' Mackay test.

for the sake of convenience it is preferable to employ those products which are normally liquids. A particularly effective anti-oxidant of the present class is the liquid condensation product' of acetone and diphenylamine sold under the trade name B'-LE by the Naugatuck Chemical Company.

The proportion of anti-oxidant employed in prepar'='-.g the stabilized dry size compositions of ti s invention depends upona number of factors, 'iong which are the particular anti-oxidant mad, and the degree of stabilization desired. Usually a size is considered suflicientiy stabilized for all ordinary purposes if it resists oxidation for about '48 hours when subjected to an accelerated oxidation treatment known as the This treatment consists in placing a sample of the stabilized size in a wire basket suspended in a water-jacketed chamber maintained at a temperature of C. A small volume of air ispassed continuously through the chamber for the desired length of time, during which time the temperature of the sample, which is a measure of the oxidation, is accurately determined. Dry rosin size containing no anti-oxidant will oxidize to a considerable extent, i. e., its. temperature will rise considerably above 100 C.. and it may even ignite and burn when subjected to this test over a period of about 48 hours, while a size stabilized according to the invention will undergo substantially no oxidation.

The optimum proportion of anti-oxidant also depends upon the composition of the size itself, a somewhat larger proportion being required for sizes containing free alkali or free rosin. Thus, for example, a neutral saponified rosin size may be rendered stable to oxidation as determined by the 48-hour Mackay testby the addition of 1.0 per cent by weight of the anti-oxidant, whereas a size containing 0.3-0.6 per cent by weight of free alkali may require the addition of 1.5 per cent by weight of the anti-oxidant to secure such a degree of stabilization. Similarly, a size containing 5.0 per cent by weight of free rosin may require the use of 2.0 per cent of the antioxidant to secure good stabilization. The type of dry size, i. e., whether it has been prepared from wood-rosin, gum rosin, or rosin which has been heat-treated to effect partial decarboxylation, is also of influence on theproportion of anti-oxidant to be used. Thus, sizes comprising saponified gum rosin usually required a somewhat larger proportion of the anti-oxidant than the other types. In general, however, it will be found that from about 0.5 to about 5.0 per cent of the anti-oxidant, based onthe weight of the rosin used in preparing the size, will be sufiicient to render any dry size substantially resistant to oxidation.

The anti-oxidant may be incorporated with the size at any convenient time during the process for the production of the size, by treatment 'f of the size after it is produced, or by treatment of the rosin prior to its saponification. Ordinarily, however, the anti-oxidant will desirably and most effectively be added to the size during its preparation by the saponification of rosin. A particularly convenient mode of effecting such addition consists in dissolving the anti-oxidant in a suitable solvent and adding the resultant solution to the mixture of water, alkali, and

- a material selected from the class consisting of liquid condensation products of aliphatic ketones with secondary aromatic amines of the benzene and naphthalene series and the liquid hydrogenarosin in the reaction vessel in which the saponification reaction is carried out. Thus, for example, about 1.0 per cent of a. ketone-amine condensation product of the present class, based on the weight of the rosin employed, may be dissolved in alcohol and added to a mixture of rosin, water, and sodium hydroxide so proportioned as to produce a size containing about 5.0 per cent free rosin, either before or during the saponification reaction. Upon completion of the reaction, the mixture may be desiccated by sprayor drum dryingto produce a dry size having the anti-oxidant uniformly distributed therethrough.

The following example illustrates one wayin' which the principle of the inventionmay be applied but is not to be construed as limiting the same:

Forty pounds of G gum rosin is placed in an tion products thereof, said anti-oxidant being present in an amount suflicient to render the composition substantially resistant to oxidation.

3. A stabilized dry size composition comprising saponified rosin and, as an anti-oxidant therefor,

a liquid condensation product of an aliphatic ketone and a secondary aromatic amine of the benzene series, said condensation product being present in an amount suflicient to render the composition substantially resistant to oxidation.

4. A stabilized dry size composition comprising saponified rosin, free rosin, and, as an antioxidant therefor, a liquid condensation product of an aliphatic ketone and a secondary aromatic amine of the benzene series, said condensation product being resent in an amount suflicient to render the composition substantially resistant to autoclave and heated to a temperature of about 149 C., after which 5.0 pounds of sodium hydrovide dissolved in 7.8 pounds of waterandheated to a temperature of about 132 C. is forced into the bottom of the autoclave under a pressure of about 125 lbs./sq. in. while venting the autoclave to maintain a pressure of about 85 lbs./sq. in. The mixture is then heated at a temperature of about 176 C. for 10 minutes, after which there is added 0.2 pounds of a liquid condensation product of acetone and diphenylamine in 3 per cent paramn oil solution. The heating is continued for 10 minutes, after which the mixture is allowed to discharge under its own pressure into a drying chamber whereby it is desiccated to form a dry powder. The dry rosin size so prepared is stable to oxidation as determined by the 48-hour Mackay test and has a 4-hour oxygen demand value of about 2.4'per cent. A dry rosin size prepared in the same manner but without the addition of the anti-oxidant ignites and burns in 13 hours when subjected to the Mackay test and has a 4-hour oxygen demand value of about 3.8 per cent.

Other modes of applying theprinciple of my invention may be employed instead of those explained, change being made as regards the materials employed, provided the ingredients stated by any of the appended claims or the equivalent of such stated ingredients be employed.

of acetone and diphenylamine in an amount sufficent to render the composition substantially resistant to oxidation.

7. A stabilized dry size composition comprising saponified rosin and, as an anti-oxidant therefor, a liquid condensation product of an aliphatic ketone and a secondary aromatic amine of an aliphatic ketone and a secondary aromatic amine ofthe naphthalene series, said condensation product being present in an amount sufficient to render the composition substantially resistant to oxidation.

' ARTHUR C. DRESHFIELD. 

